Facial paralysis may arise from injury to the facial nerve as a result of Bell's Palsy, trauma, surgical damage, tumors, infections and various other conditions. The paralysis may be a temporary or permanent condition. Patients suffering from facial paralysis may experience such symptoms as lagophthalmos, asymmetry or distortion of facial expression, drooling, speech difficulty and the like. Lagophthalmos (the inability to fully close the eye) leaves the eye exposed and may result in serious damage or injury to the eye. For example, excessive exposure of the eye may cause pain, discomfort, ocular irritation, conjunctival desiccation, conjunctivitis, epiphora and the like and may lead to the development of keratitis, corneal abrasion or ulceration, and even blindness. Thus, a critical consideration in the treatment of patients with facial paralysis is the protection of the eye.
Depending upon the ability of the patient to partially close the eye, the eye may be protected by lubricating the eye with ophthalmic drops, ointments protective moisture chambers, occlusive bubbles and the like. However, repeatedly lubricating the eye is cumbersome for the patient, often causes obscured vision and discomfort, and may not sufficiently protect the eye. Surgical procedures, such as tarsorrhaphy (suturing the eyelids together) and implanting various prosthetic devices in the eyelids, may be used to improve eyelid closure and reduce exposure of the eye. Suturing the eyelids together provides some protection for the eye but generally prevents active eyelid closure, restricts peripheral vision and may be cosmetically unattractive to the patient. Moreover, the lids may be deformed when the procedure is reversed, particularly if the procedure involves the use of permanent sutures and the excision of soft tissue. Prosthetic devices such as tantalum gauze mesh, silicone rubber elastic strips, stainless steel springs and magnets implanted in the upper and lower lids provide some amount of active eyelid closure. However, the prosthetic devices have been associated with a significant occurrence of infection and extrusion of the prosthetic device from the eyelid. Furthermore, the procedures used to implant the prosthetic device may be difficult to master and a second procedure may be required to adjust the placement or fixation of the prosthetic device.
Gold weight implants have also been used in the surgical treatment of lagophthalmos. The gold weights are implanted in the upper eyelid and secured to either the tarsal plate, orbital septum or levator aponeurosis. When the levator muscle is relaxed, the upper eyelid is lowered by the force of gravity, substantially closing the eye. The gold implants are available in several weights to provide the required amount of assistance for the eyelid to close. The implants are generally formed in the shape of a cylindrical arc and have a radius which conforms to the curvature of the eye. One type of gold weight implant is shaped to conform to the curvature of the cornea; however, the steeper inclination of the implant concentrates the weight of the implant on a small area of the eye, often inducing more astigmatism than other prosthetic devices. Because of the steep inclination, the implant is also more likely to extrude from the eyelid.
The optimum weight required for eyelid closure is determined by temporarily attaching the implant to the exterior of the eyelid with rubber adhesive, dermatome glue, tincture of benzoin, adhesive tape and the like. The effect of the implant on the eyelid as the patient looks up and down is observed, and the process is repeated with an implant having a different weight as necessary. When the patient is looking straight ahead, the gold weight preferably holds the lid about one millimeter lower than the normal eyelid. The selected gold implants are then removed from the eyelid, sterilized and implanted in the upper lid. The implant is secured to either the tarsal plate, orbital septum or levator aponeurosis depending upon whether pretarsal or septal placement is desired. If facial paralysis is a temporary condition, the gold weight implant may be easily removed once eyelid function is regained.